Geological map of Iğdır province
The geological map of Iğdır province prepared according to today's provincial borders is given in Fig. 2, and the formations related to geological times, places where they are seen, calculated area and ratio values are given in Table 1.
Table 1
Events of geological times in Iğdır province
Geological times and formations | Locations | Area | Ratio |
ha | % |
4 | Andesite | Mountainous areas and slopes | 44011 | 11.98 |
Undifferentiated Quaternary | NW of Tuzluca, Iğdır plain | 91787 | 24.98 |
Alluvial Fans, Slope Debris | N of Tuzluca, slopes in the S and SE | 31045 | 8.45 |
3–4 | Basalt | Mountainous areas and slopes | 118905 | 32.36 |
Continental Clastic Rocks | E and SE of Tuzluca, slopes in the S | 20809 | 5.66 |
3 | Pyroclastic Rocks | E of Iğdır, Mountainous areas in the S | 19220 | 5.23 |
Continental Clastic Rocks | W of Tuzluca | 1062 | 0.29 |
Clastic and Carbonate Rocks | Surrounding of Tuzluca | 19341 | 5.26 |
2 | Granitoid | NW of Tuzluca | 117 | 0.03 |
Ophiolitic Melange | Tuzluca batısı ve güneybatısı | 20790 | 5.66 |
Pelajik kireçtaşı | W and SW of Tuzluca | 219 | 0.06 |
Undifferentiated basic ve ultrabasic rocks | NW border of Tuzluca | 24 | 0.01 |
1 | Carbonate Rocks and Clastic Rocks | SE of Aralık, NW of Dilucu | 112 | 0.03 |
Total | 367442 | 100 |
According to the geological map and spatial distribution of Iğdır, formations were determined for 4th time Andesites (44011 ha, 11.98%), Undifferentiated Quaternary (91899 ha, 24.98%), Alluvial Fans and Slope Debris (31045 ha, 8.45%); for 3-4th time Basalts (118905 ha, 32.36%), Continental Clastic Rocks (20809 ha, 5.66%); for 3rd time Pyroclastic Rocks (19220 ha, 5.23%), Continental Clastic Rocks (1062 ha, 0.29%), Clastic and Carbonate Rocks (19341 ha, 5.26%); for 2nd time Granitoid (117 ha, 0.03%), Ophiolitic Melange (20790 ha, 5.66), Pelagic Limestone (219 ha, 0.06%), Undifferentiated Basic and Ultrabasic rocks (24 ha, 0.01); and for 1st time Carbonate and Clastic Rocks (112 ha, 0.03%).
The general characteristics of the large soil groups of Iğdır province (GDRS, 1998; Anonymous, 2023) and the geological formations on which they are located were presented together in Table 2.
Table 2
Characteristics of large soil groups-geological formations
Soil properties | Large soil groups |
Basaltic (X) | Chestnut CE) | Hydromorphic (H) | Colluvial (C) | Regosol (L) | Braun (B) | Alluvial (A) |
Colour | Grey-black | Dark | Dark | Light | Light | Dark | Dark |
Texture | Heavy clayey | Much clayey | Fine | Coarse | Coarse | Fine | Fine-Coarse |
Profile | Undeveloped | ABC | Under water | AC | AC | ABC | Young A |
Depth | 30–50 cm | 30–50 cm | 30–50 cm | 30–50 cm | 50–90 cm | < 20, 30–50 cm | > 90 cm |
pH | 7-8.5 | 7-8.5 | 5 | 7-8.5 | 7-8.5 | 7–9 | 7-8.5 |
Lime | 0 | 15–30 | 0 | 0 | 0 | 30–55 | 30–55 |
Organic M. | 0–1 | 3–4 | > 4 | 0–1 | 3–4 | 2–3 | > 4 |
Fertility | Lower | Good | Under water | Lower | Lower | Good | Good |
Problem | Stony | Slopy | Airless | Coarse stone | Weak Form. | Slopy | Weak layer |
Slope | > 12° | 6–15° | 0° | > 15° | > 15° | 2–6° and > 12° | 0–2° |
Drainage | Bad | Good | Bad | Bad | Bad | Good | Poor-Good |
Bottom layer | Basic | Gypsum layer | Under water | Young | Stoneless | Lime-Gypsum | Ground water |
Main M. | Igneous | Igneous | Igneous | Sedimentary | Sedimentary | Sedimentary | Transported |
Ordo | Azonal | Zonal | İntrazonal | Azonal | Azonal | Zonal | Azonal |
Geology | A, B | A, B | A, B | AF, SD | CaCR, CCR | OM, CaCR | UQ, CRaCR |
M: Matter; A: Andesite; B: Basalt; AF: Alluvial Fan; SD: Slope Debris; CaCR: Clastic and Carbonate Rocks; CCR: Continental |
Clastic Rocks; OM: Ophiolitic Melange; UQ: Undifferentiated Quaternary; CRaCR: Carbonate Rocks and Clastic Rocks.
When examining soil properties, the geology of the region should also be known. Because the geological structure of a certain region is an effective factor in shaping the parent soil materials in that region (Everest and Özcan, 2018). As a common view, Andesite is formed from the decomposition of Basaltic magma at depth (Seyhan, 1971) and both are hard and durable in structure. Basalt (3-4th Time) and Andesites (4th Time) cover the south of Iğdır province in the east-west direction and are overlain by Basaltic (X), Chestnut (CE) and Hydromorphic (H) soils. When basic igneous rocks decompose, they cause clay-rich soils to form. Basaltic, Chestnut soils and Hydromorphic soil properties confirm this explanation. These large soil groups located in high and rugged geography are soils formed on site and have the characteristics of the geological formation and parent material on which they are located.
Sedimentary rocks are the most common rock type on earth. They cover approximately 75% of the Earth's surface (Wilkinson et al., 2008) and approximately 8 percent of the Earth's crust (Buchner and Grapes, 2011). The most important feature of sedimentary rocks is that they show a layered structure. Differences in colour, texture, composition and hardness of the layers in question help distinguish them from each other (Dirlik, 2023). Alluvial cones and slope debris on the sloping lands in the south of Iğdır and the district of Aralık and Colluvial (C) soils on the Undifferentiated Quaternary sedimentary rocks in the west of Iğdır were formed on young and transported parent material. The properties of colluvial (K) soils show a strong similarity with the geological structure and parent material on which they are located.
Around the Tuzluca district, from the Miocene period Clastic and Carbonate Rocks, the Clastic ones were brought to the environment where they were deposited, foreign (allochthonous); Carbonates, on the other hand, are autochthonous formations because they were formed in the environment in which they were deposited. Although sudden events stop carbonate deposition, they cannot stop the deposition of clastics (Derman, 2004). Continental Clastic Rocks of the Pliocene-Quaternary period can accumulate in different environments such as desert, delta, lake, glacier, stream and shelf. There is no obvious similarity between the Regosol (L) soils formed on the Clastic and Carbonate Rocks of the Miocene and Pliocene periods and the Continental Clastic Rocks, on the other hand, sand-sized grains resulting from volcanic eruptions accumulate on Colluvial (C) soils accumulated at the foothills of volcanic mountains and Regosol (L) soils are formed. There are significant similarities between colluvial (C) and Regosol (L) soil properties, except for organic matter content.
In the Anatolian plate, Neotethys remains are represented from top to bottom by ophiolites, ophiolite base metamorphisms and ophiolitic melanges (Robertson, 2002). Neotethys consists of two oceanic facies, southern and northern (Şengör and Yılmaz, 1981). Ophiolites formed on the subduction zone, which is important in the Neotethyan evolution process of Turkey (Dilek and Thy, 2009), show a series of events compatible with each other during the formation and settlement periods (Rızaoğlu et al., 2019). No description could be made between the Ophiolite Melange in the west of Tuzluca, which is connected to the Kağızman ophiolite, which is one of the northern ophiolites, and the Brown soils on the surface. It is thought that there is a relationship between Clastic and Carbonate Rocks and Brown soils with a calcification basis and lime accumulation layers.
Since the alluvial soils on the Unseparated Quaternary sediments located in the Iğdır plain and the northwestern Aras River were formed as a result of transportation, their similarity with the Unseparated Quaternary is the accumulation (sedimentary) phenomenon.
Hydrographic map of Iğdır province
According to the hydrography, basin and SPI distribution maps prepared with the help of GIS for Iğdır province (Fig. 3), the rivers of Iğdır province flow in the south-north direction, depending on the elevation, and consist of seasonal (flood) surface flows. Many of the rivers drain their waters into the Aras River and form the sub-basins of the Aras River. The flow rate of the rivers is not regular, and they mostly have dry stream beds. However, in the spring months (March-May), flow rates in riverbeds increase due to heavy rains, snow and glacier melting. These waters, which suddenly and rapidly flow to the surface within the borders of Iğdır province, cause flood events to occur due to the direct increase in the flow rate of the rivers (Utlu and Ghasemlounia, 2021).
Morphological and lithological characters are primarily effective in the formation and development of a natural drainage network. In other words, the drainage structure formed in a region is a reflection of factors such as basin form, lithological structure, soil properties, slope status and climate characteristics in the region (Al Saud, 2009). When we pay attention to the drainage of Iğdır province, it is seen that the most common drainage type is the dendritic drainage network. There are many side branches on the 5 main drainage trunks from west to east. The main trunks are generally parallel or semi-parallel to each other. This is related to the fact that the mountainous area and foothills in the south of Iğdır have high slopes (12–64°) (Karaoğlu and Erdel, 2022a). If the slope slopes are dominant in one direction in large areas, as is the case from south to north in Iğdır province, a parallel drainage type occurs (Görüm, 2018). Furthermore, in areas fragmented by parallel and semi-parallel faults, consecant streams following newly emerged fault scarps (Erinç and Bilgin, 1956) or subsecant (steep or diagonal) valleys that conform to previous fault lines at the time of rejuvenation are also suitable areas for the emergence of this drainage type (Görüm, 2018).
6 sequences emerged as stream bifurcations, and depending on these values, there is a high water erosion potential and risk in the current period of surface flow. It is seen that there are 13 river sub-basins within the borders of Iğdır province, and these basins, except W13, generally correspond to small-scale basins, and there is a large water collection basin in Mount Ararat and its surroundings. The increased amount of surface flow, especially from steep slopes, as a result of heavy rains and snow-glacier melting, increases the risk and potential of erosion with the high slope and high abrasion power in narrow and deep channels.
Understanding the sediment transport load and the potential of accumulation and transport activities on drainage channels in river basins is of great and critical importance, especially in terms of sustainable geography and basin management (Bizzi and Lerner, 2015). SPI values for Iğdır province decrease from 14.6 to -13.8 in the south-north direction from the 5137 m peak to the 788 m depression plain. High values were calculated in the mountainous areas to the west and south of Iğdır. This is because increased gully erosion due to insufficient vegetation. These values show that the potential and risk of downslope surface flow and water erosion are high in the spring months. In other words, the transportation of tuff material in Aralık wind erosion area, which is the second largest one in Türkiye and located in the northeast of the depression plain, is carried out by water erosion.